This invention relates generally to a troubleshooting method, for service technicians operating in the field, to test a system with variable speed motors and, to provide the flexibility to individually eliminate the system components as the source of the system error by the strategic use of component simulator circuits.
Specifically, this invention relates to a high efficiency variable capacity condensing gas furnace equipped with an improved diagnostic circuitry to allow a service technician to test the furnace in the field. Two improved troubleshooting accessory simulator circuits are provided for strategic use to individually eliminate furnace system components as the source of the system error.
Existing variable speed gas furnaces operating in the field require the service technician when troubleshooting to make many voltage measurements across various components of the furnace system. This can be a cumbersome, complex and costly process. There is a need for a method of troubleshooting a variable speed gas furnace in the field that is not complicated or lengthy, and that does not require sophisticated equipment.